1. Field of the Invention
This invention relates to a valve for regulating the flow of high temperature, abrasive fluids and more particularly, to a valve constructed primarily from a combination of refractory and ceramic materials for use in regulating the flow of gas and char particles encountered in a coal gasification process.
2. Description of the Prior Art
It is well known to provide a high temperature valve with a refractory lining as disclosed in the following United States Patents:
______________________________________ 1,995,727 - Wetherbee 3,167,087 - McInerney 2,029,864 - Elgaard 3,167,088 - McInerney 2,352,799 - Newton 3,309,286 - Alderman 3,030,977 - Werner 3,448,761 - Feinman 3,052,253 - Priaroggia 3,701,359 - Worley et al. et al. 3,150,680 - Becker et al. ______________________________________
It is further known to provide a valve having removable valve elements as disclosed in the following United States Patents:
______________________________________ 2,575,464 - Olsen 3,537,682 - Priese 2,902,254 - Conway et al. 3,726,306 - Purvis ______________________________________
Synthetic fuel gas is commonly produced by reacting a carbon source, such as coal, with steam at a high temperature. The process is called coal gasification and the reaction generally is carried out under a reactor pressure of about 550 psig and a temperature in the range of about 1800.degree. F. Hot coal particles are metered into a gasification reactor through a high temperature valve. Another high temperature valve is required at the bottom of the gasification reactor to allow for the flow of gas and an unreacted (char) portion of the coal.
The valves used in the coal gasification apparatus must have high thermal resistance to withstand very high temperatures on the order of about 1800.degree. F. or higher. The valves must also be resistant to abrasion and erosion caused by the hot gases and solid particles, and must have high strength capable of withstanding the pressure differential between reactor and conduit pressure.
High temperature, high cost super-alloy materials are commonly used to fabricate the valves used with coal gasification apparatus, but such materials operate at or near the limit of their physical properties when subjected to temperatures in the range of about 1800.degree. F., and are prohibitively expensive.